A light emitting device (LED) is a p-n diode for converting electrical energy into optical energy and may be generated by a combination of Group III and V elements. An LED can implement various colors by adjusting a composition ratio of compound semiconductors.
An LED emits energy corresponding to an energy gap of a conduction band and a valance band by combining electrons of an n layer and holes of a p layer upon applying a forward voltage. This energy is emitted in the form of heat or light. An LED emits energy in the form of light.
For example, nitride semiconductors have been spotlighted in the fields of optical devices and high-output electronic devices due to high thermal stability and wide bandgap energy thereof. In particular, a blue LED, a green LED, an ultraviolet (UV) LED, etc. using nitride semiconductors are widely used.
In the related art, there is technology of providing an electron blocking layer between an active layer and a second conductivity type semiconductor layer to prevent overflow of electrons to increase light emitting efficiency. However, an electron blocking function was not properly performed.
In addition, in the related art, since carriers are concentrated on the center of a pad electrode, light emitting efficiency may deteriorate.